PTP-layer LTPs do not refer to its clock

[niloda]

The synch-ltp-spec class includes the embedded-clock attribute, which references the clock instance to which the LTP belongs. This establishes a bidirectional relationship between the clock and the LTPs: through synch-ltp, the clock can reference its associated LTPs, and conversely, each LTP can reference its associated clock.

However, for LTPs whose layer-protocol-name is set to LAYER_PROTOCOL_NAME_TYPE_PTP_LAYER, the embedded-clock attribute is not present. As a result, the relationship becomes unidirectional—i.e., the clock can reference the LTPs, but the LTPs cannot reference the clock.

Proposed enhancement:
To re-establish bidirectional association for PTP-layer LTPs, it is proposed to introduce a new ptp-ltp-spec class, specifically designed to extend LTPs whose layer-protocol-name is LAYER_PROTOCOL_NAME_TYPE_PTP_LAYER.

This class would:

• Extend the LTP with PTP-specific attributes and behaviors.
• Include an embedded-clock reference, consistent with the synch-ltp-spec, to explicitly link the PTP LTPs to its corresponding clock.

[openBackhaul]

The meaning of the embedded-clock attribute is assumed to allow pointing to a clock relevant to an individual LTP exclusivly, but not to a local clock that is serving multiple LTPs.
This is a case of implementation that is not relevant to all known microwave devices.

Proposal to the LF ONMI x-haul meeting on 10th of December 2025:
The SynchLtpSpec::_embeddedClock attribute shall be deleted from the Synch modelling.

[PrathibaJee]

Currently, the attributes ,encompassed-clock and phase-aligned-clock in the clock-spec is referencing the attribute SynchLtpSpec::_embeddedClock.

leaf-list encompassed-clock {
      type leafref {
        path "/core-model:control-construct/core-model:logical-termination-point/synchronization:embedded-clock";
        require-instance false;
      }
      description
        "A clock may be emergent from and may effectively encompass several clocks in a resilient solution.";
    }
    leaf-list phase-aligned-clock {
      type leafref {
        path "/core-model:control-construct/core-model:logical-termination-point/synchronization:embedded-clock";
        require-instance false;
      }
      description
        "One or more clocks can be actively phase aligned (this is especially relevant in a hitless resilience scheme).";
    }

Removing this attribute will impact these dependent attributes. So, the proposed solution shall be discussed again to solve this problem.

Note

Also , "embedded-clock" is the only attribute inside the synch-ltp-spec class. So, while removing this attribute, that class shall also be deleted.

[openBackhaul]

Problem:
The SynchLtpSpec::_embeddedClock attribute could not be deleted, without deleting the ClockSpec::_encompassedClock and the ClockSpec::_phaseAlignedClock attributes, too.

Proposal to the LF ONMI x-haul meeting on 8th of April 2026:
The decision made on 10th of December 2025 shall be changed from deleting the SynchLtpSpec::_embeddedClock attribute into changing its comment.

The following formulation shall be added as a comment to the SynchLtpSpec::_embeddedClock attribute:
"The embedded-clock attribute is meant for pointing to a clock relevant to an individual LTP exclusively. It is not for referencing a local clock that is serving multiple LTPs."